Intrauterine Treatment of Fetal Supraventricular Tachycardia Complicated By Fetal Hydrops: Livebirth At Term

Introduction: Fetal tachycardia is a rare complication during pregnancy, with supraventricular tachycardia (SVT) being a common cause of a primary sustained fetal tachyarrhythmia. If developed early in pregnancy, it can lead to non-immune fetal hydrops (FH). Multidisciplinary approach is mandatory between pediatric cardiologists (both paediatric and adult), neonatologist, and maternal-fetal medicine specialist. Case Presentation: We present a case of fetal SVT, complicated with FH at 24 weeks’ gestation, which was successfully treated with transplacental flecainide to emphasize the need for prenatal evaluation of pregnancies complicated by FH and provision of appropriate treatment to optimize outcome. 35-year-old MPLK; with a gravidity of 1 and parity 0, was referred to our Fetal Medicine Clinic due to an increased fetal heart rate (FHR) of 243 beats per minute during a routine fetal anatomical survey scan at 22 weeks gestational age (GA). The pregnant woman and the fetus had no clinical symptoms, and clinical examinations and investigations revealed no organic lesions. The fetus developed congestive heart failure evidenced by cardiomegaly, pericardial effusion, ascites, and skin edema at 24 weeks’ gestation. The couple made an informed decision for transplacental antiarrhythmic therapy which resulted in successful fetal cardioversion, with minimal maternal side effects. Delivery was conducted at 37W GA, and baby is currently 4 months old and well. Conclusion: Prenatal evaluation of pregnancies complicated by fetal hydrops is necessary to determine the underlying etiology and provide appropriate treatment to optimize outcome.